Overview of Renewables in the ERCOT System. Julia Matevosyan Lead Planning Engineer, Resource Adequacy

Transcription

1 Overview of Renewables in the ERCOT System Julia Matevosyan Lead Planning Engineer, Resource Adequacy Wind Integration Workshop Stockholm, October 2018

2 What is ERCOT The interconnected electrical system serving most of Texas, with limited external connections 90% of Texas electric load; 75% of Texas land 73,308 MW peak demand, July 19, generation units ERCOT connections to other grids are limited to ~1,250 MW of direct current (DC) ties, which allow control over the flow of electricity 30 MW with CFE at Eagle Pass 100 MW with CFE at Laredo Texas RE 220 MW with SPP 600 MW with SPP 300 MW with CFE at McAllen 2

3 Wind Generation Capacity September 2018 Installed Wind Capacity: 21,190 MW Wind Generation Record (instantaneous): Output: 17,541 MW Feb. 19, 2018, 10:05 p.m. Penetration (load served): 54% Oct. 27, 2017, 4 a.m. Total Load = 28,416 MW Future outcomes uncertain 3

4 Utility Scale Solar Generation Capacity September 2018 Future outcomes uncertain 4

5 Changing Resource Capacity Mix: Variability + Flexibility Note: 2020 capacity numbers include planned projects with commercial operation date through 2020, as well as account for confirmed retirements and mothballs 5

6 Before it all started Advantages: Great wind & solar resources in the West and Panhandle regions Load Resources with underfrequency relays provided a portion of frequency containment reserve (at 59.7 Hz, full resp. in 0.5 second) All generators were required to provide governor response (5% droop, 36 mhz deadband) All generators were dispatchable on the market Challenges: Scarce or no transmission to renewable-rich areas Largest contingency to protect against is high compared to system size 15-minute, zonal market No experience with renewable forecasting and operation Uncertainty over essential reliability services. 6

7 Competitive Renewable Energy Zone Transmission Planning started in 2005 Construction started in 2010 Completed in January 2014 Designed to serve 18.5 GW of wind resources ~3600 miles of 345 kv transmission Project cost: ~$6.9 billion Lines are open-access; use not limited to wind 7

8 Wind Forecasting, Present Centralized forecasting Improving forecast accuracy Wind forecasting in use since 2009, initially 48-hour outlook Solar forecasting was introduced in 2015 Currently, ERCOT uses a 168-hour rolling forecast with hourly resolution for all wind/solar resources. Average hour ahead wind forecast error is 3.35% in

9 Nodal energy Market, 5-min Real Time Dispatch, 2010 Voluntary Day-Ahead Market, where Ancillary Services are procured, cooptimized with energy; Generators self-commit; ERCOT makes residual reliability commitments; In Real-Time all generators (including renewables) submit offers for generation output Real-Time market clears every five minutes, using the cheapest generation to serve the load, subject to transmission constraints All generators (including renewables) receive output level instructions and locational marginal prices 9

10 Governor-like response from Wind and Solar, 2012 Requirement for all wind and solar resources with interconnection agreements after 2008 to provide a governor-like response; To date, about 2000 MW of older plants are exempt; In 2016 the deadband for all generation changed to from 36 to 17 mhz 60,05 Wind Resource Response to Low Frequency 07/13/ ,075 Wind Resource Response to High Frequency 08/25/ , , ,038 59, , , , , , , ,963 59, , , :25 13:28 13:31 13:34 13:37 13:40 Frequency Nominal Frequency MW 59, :13 16:16 16:19 16:22 16:25 16:28 Frequency Nominal Frequency MW 10

11 Weak Grid Issues in Panhandle, present ~ 5.5 GW planned, ~4 GW in service (all wind generation) ~2.8 GW planned in the nearby area No local load or synchronous generators Voltage support and system strength issues 11

12 Ancillary Services Regulation Up 157 to 687 MW* Regulation Down 156 to 604 MW Responsive 1.Primary Frequency Response 2.Load Resources on Under Frequency Relays (UFR) 2,300 to 3,200 MW Non-Spin 967 to 2,361 MW *The numbers are showing 2018 AS amounts 12

13 Frequency Containment Reserve Based on Inertia Conditions and Load Participation,

14 Reliability Risk Desk, Situational Awareness, 2016 Inertia Monitoring and Forecasting Critical Inertia alerts Reserve Sufficiency Monitoring Overall Capacity Availability Tool 14

15 Proposed Ancillary Service Framework Changes, 2018 Last Edited on /16/2018 Current Framework NPRR 863 With STEC Comments (4/26, 8/2) and ERCOT Steel Suggestions Regulation Regulation 157 to 687 MW* 157 to 687 MW* No Change Responsive Reserve Service 1. Primary Frequency Response 2. Load Resources on Under Frequency Relay (UFR) minute ramp 2,300 to 3,200 MW* Non-Spin 967 to 2,361 MW* Overall A/S: 3,807 to 5,958 MW* Responsive Reserve Service (RRS) Fast Frequency Response (FFR) Load Resources on UFR Primary Frequency Response (PFR) 2,300 to 3,200 MW* ERCOT Contingency Reserve Service (ECRS) 10 minute ramp Load Resources may or may not be on UFR 508 to 1,644 MW** Non-Spin 0 to 1,180 MW* FFR Triggered at Hz and full response in 15 cycles Once deployed, sustain for up to 15 mins. Once recalled, restore within 15 mins PFR PFR capable capacity reserved on generators or Controllable Load Resources (CLR) Minimum 1,150 MW must be provided by resources capable of PFR Load Resources on UFR Triggered at Hz and full response in 30 cycles Sustain until recalled. Once recalled, restore within 3 hours Beyond the minimum PFR, up to 60% of total FRS can come from Load Resources on UFR or FFR. Generation Online or offline capacity that can be converted to energy within 10 minutes Dispatched by SCED Load Resources (UFR not required) Up to 50% of ECRS capacity can come from Load Resources with or without UFR Once deployed, must respond within 10 minutes. Restoration within 3 hours No protocol changes. Proposed methodology for Non-Spin Reserve Service quantities in this framework - quantities computed using 2018 A/S Methodology are reduced by ECRS quantities. Overall A/S: 3,807 to 5,958 MW* *Quantities computed/estimated using 2018 Ancillary Service Methodology. **Quantities estimated using this reference. For Discussion Purposes Only. The intent of this slide is to represent NPRR 863 (with ERCOT comments from 7/6/2018). Protocol language prevails to the extent of any inconsistency with this one page summary. 15

16 Key Takeaways System operators in areas with growing amounts of renewables face challenges with system balancing (uncertainty, ramping, variability, voltage and frequency control); Granular real-time dispatch and accurate forecasting is key; Real-time awareness tools in the control room are essential for efficient and reliable operations with high levels of renewable resources; Ancillary Services can satisfy essential reliability needs for the system Use market-based solutions as much as possible Some of the reliability requirements need to be implemented through grid codes. Modern renewable generation technology can provide grid support and AS. Resolving integration issues increasingly requires ongoing coordination between grid/market operators, generation owner/operators and turbine/control manufacturers 16

17 Thank you! Questions? Julia Matevosyan 17